Although infarct location may predict prognosis after primary percutaneous coronary intervention (PCI) for ST elevation myocardial infarction, previous studies were powered insufficiently to be able to show whether this association is independent of peak creatine kinase (CK) or left ventricular ejection fraction (LVEF).
A large-scale, prospective, observational, single-center study was performed including all patients who underwent primary PCI between 1991 and 2004 in Zwolle (The Netherlands). The association between infarct location and 1-year outcome, was compared with the prognostic impact of peak CK and LVEF.
Of 4990 patients, 2485 (49.8%) had an anterior infarction. Patients with anterior myocardial infarction had a higher peak CK (2960 vs. 2009 U/l, P<0.001) and a lower LVEF (40.0 vs. 50.0%, P<0.001). Mortality within 1 year was higher in patients with anterior infarction as well as in those with a high peak CK or a low LVEF. After multivariate analyses, patients with anterior infarction still had an increased risk of a high peak CK, a poor LVEF, and also a higher 1-year mortality, odds ratio (OR) 1.35 [95% confidence interval (CI) 1.07–1.70]. Low LVEF was a significant stronger predictor of 1-year mortality, OR 4.4 (95% CI: 2.4–7.8), compared with peak CK, OR 2.0 (95% CI: 1.6–2.5) or anterior location, OR 1.6 (95% CI: 1.3–2.0).
In patients undergoing primary PCI, location of infarction is an important independent predictor of high peak CK, low LVEF, and increased mortality. LVEF is a strong predictor of 1-year mortality.